feat(server): auto-resolve Sentinel URL and polish setup UI

Ensure a Sentinel endpoint from instance FQDN/IP when enabling, use process dialogs for validation with install state, and tidy server create, boarding, metrics empty state, and log timestamps.

tests/Unit/LogTimestampDisplayTest.php

@@ -0,0 +1,9 @@
+<?php
+
+test('deployment log timestamps omit microseconds', function () {
+    $helper = file_get_contents(dirname(__DIR__, 2).'/bootstrap/helpers/remoteProcess.php');
+
+    expect($helper)
+        ->toContain("->format('Y-M-d H:i:s')")
+        ->not->toContain("->format('Y-M-d H:i:s.u')");
+});